Child resistant packaging is known for being both a blessing and a curse. It is a great concept for preventing children from opening potentially dangerous materials such as medications, but for adults, especially the elderly, such packaging can be a nuisance.
Because of deteriorating health, the elderly tend to rely on medication more than the average person. However, simply making medication more easily accessible to the elderly bears with it the risk that the contents of the package could be accessible to children who could be seriously injured if they obtain access to the contents of a medicament package and ingest the medicaments contained therein.
The aforementioned problems are recognized generally in the packaging industry, particularly the pharmaceutical industry. Numerous articles have been written on the subject. See for example "The Dual Vial" published in the Fall 1988 edition of Stout magazine
Attempts to deal with these problems are also reflected in the patent literature. For example, U.S. Pat. No. 3,993,208 issued to Ostrowsky on Nov. 23, 1976 discloses a safety closure means wherein the shoulder on a container is formed with a pair of diametrically positioned locking lugs. The mating closure is formed of thermoplastic material and has a top end wall and a depending annular inner wall in addition to a depending outer annual skirt spaced from the inner wall. The inner wall includes threaded means for engaging the neck of the container to secure the cap to the container in a closed position. The outer skirt of the cap has a pair of diametrically positioned radially extending locking lugs adjacent the lower end of the skirt. The cap locking lugs are adapted to pass inwardly of the container locking lugs and to be compressed radially inwardly when the cap is rotated to a cap closing position. As the cap lugs move past the container locking lugs, the cap lugs are released from their compressed state so that they extend outwardly beyond the engaging edges of the container locking lugs. This prevents the closure from being unscrewed until the outer skirt of the closure is manually squeezed radially inwardly adjacent the cap locking lugs to permit them to clear engagement with the edges of the container lugs as the cap is unscrewed from the container.
Under normal in use conditions, removal of the closure of Ostrowsky requires squeezing the outer skirt of the closure sufficiently to disengage the lugs on the container and simultaneously unscrewing the closure with the same hand used to apply the squeezing force. This may be difficult, particularly for elderly individuals who may have impaired manual dexterity in their fingers.
In addition, the closure of Ostrowsky visually reveals how the interlocks must be overcome in order to remove the closure. A child having sufficient strength to depress the closure skirt may have sufficient intellect to defeat the interlock and remove the closure.
Another prior art attempt to overcome the aforementioned problems is disclosed in U.S. Pat. No. 4,520,921 issued to Vissing on June 4, 1985. The Vissing patent discloses a semi-rigid type container having a cap portion with a special mating relationship In the illustrated embodiment, the cap comprises a cylindrical portion with an enlarged upper edge to facilitate gripping. A hole, or a pair of holes, may be provided in the skirt of the cap. The mating container to which the cap is applied has a reduced thickness area with a protruding boss or a pair of bosses. The reduced thickness portion of the container deforms when pressure is applied to the pressure point so that the cap can slip over the container. When pressure is released from the pressure point the boss or bosses on the container are allowed to enter the mating hole or holes in the cap. If desired a tapered lead-in ramp can be used to seat the boss on the container in a mating hole in the cap. The cap is removed by squeezing the pressure point or points to disengage the boss or bosses on the container from the hole or holes in the cap.
A potential difficulty, from the standpoint of child resistance, is that a simple squeezing force applied about the periphery of the container could inadvertently lead to deformation of the pressure point or pressure points of the container of Vissing, thereby permitting complete removal of the cap without the need for deliberate action on the part of the person squeezing the container.